Samus, as much as she hates to admit it, occasionally does need sleep (preferably outside of an office). She had been working hard lately. Between missions and on-ship shenanigans she was legitimately tired, which is why she was leaving at this odd hour of the night to maybe sleep for a couple hours before returning to duty bright and early tomorrow.

But first she needs to investigate something. A usually empty office had a light on.

She doesn't knock. It's technically her building, after all.